Obama got his bill passed while seeming magnanimous in the public eye. If he concludes that the Republicans are not acting in good faith a better bill can emerge out of the Conference Committee without the expectation of Republican votes.
The most important factor is will the final bill work? If it does the Republicans will have hurt themselves for a generation. If it doesn't Obama's reelection chances in 2012 will be endangered.
So after an initial effort at bipartisanship it seems that now Obama should simply focus on passing the best bill possible. There is still plenty of time to do it.